This paper contains the results of the forest-tundra soils studying. The key sites were situated on the permafrost territory, which is under scrutiny in connection with the global climate changes. The soil position in landscape, parent rock texture, vegetation conditions and thickness of organic horizons were taken into account. On the base of seasonal thawing or active layer depth measurements and soil temperature vertical gradients calculating, four main soil groups which are different in their thermal properties were identified. The physical-chemistry properties are rather close in various soil types. Similarities in the profile distribution of humus fractions are also revealed in the soil humus formed under different conditions. Despite of estimated relatively low level of carbon stocks in forest-tundra soils, half of them exist in mobile humus forms, which are less stable.  ata on the soil thermal regime types and stocks of different humus forms in soils of various conditions are useful  or long-term forecasting of soil status.

This paper contains the results of the forest-tundra soils studying. The key sites were situated on the permafrost territory, which is under scrutiny in connection with the global climate changes. The soil position in landscape, parent rock texture, vegetation conditions and thickness of organic horizons were taken into account. On the base of seasonal thawing or active layer depth measurements and soil temperature vertical gradients calculating, four main soil groups which are different in their thermal properties were identified. The physical-chemistry properties are rather close in various soil types. Similarities in the profile distribution of humus fractions are also revealed in the soil humus formed under different conditions. Despite of estimated relatively low level of carbon stocks in forest-tundra soils, half of them exist in mobile humus forms, which are less stable.  ata on the soil thermal regime types and stocks of different humus forms in soils of various conditions are useful  or long-term forecasting of soil status.